I refuse to help someone if they're having trouble with a Mac. Seriously, those things are so easy to use they're difficult.
It makes me especially mad if I see someone with horrendous grammar on a desktop. We've moved past typewriters, where a little mistake required you to take out the paper, white out the error, and feed it back through, starting at the correct spot. With word processors, it's just the backspace key. There is really no excuse for bad grammar using a computer.